Ibrahim Datuk Tan Malaka, (born 1894—died April 16, 1949, Blitar, Java) Indonesian Communist leader who competed with Sukarno for control of the Indonesian nationalist movement.

Tan Malaka was a Minangkabau (a people of Sumatra) and a schoolteacher. When he returned in 1919 from Europe, where he was educated, he began to espouse Communist doctrines. The Communists had been working with the leading nationalist group, the Sarekat Islām (Islāmic Association) but in 1921 they split off and moved in the direction of revolutionary action, still trying to take with them local branches of Sarekat Islām. The following year Tan Malaka attempted to convert a strike of government pawnshop employees into a general strike, but the effort failed, and Dutch officials ordered him to leave the Dutch East Indies.

Tan Malaka represented Indonesia at the Fourth Congress of the Comintern (Communist International) in 1922, when he was appointed Comintern agent for Southeast Asia and Australia. He opposed as premature a Communist-backed rebellion in 1926 and was blamed by its proponents for the uprising’s failure. The next year, however, he organized a group in Bangkok called the Indonesian Republic Party; its aim was to develop underground cadres to work in Indonesia. The party gained strength, but with little visible success in weakening colonial rule.

Tan Malaka returned to Java in 1944, during the Japanese occupation in World War II, and afterward competed for power against Indonesian president Sukarno. Sukarno, however, outmanoeuvred Tan Malaka by bringing Sutan Sjahrir to power as prime minister. Tan Malaka responded by creating a coalition, called the Persatuan Perdjuangan (United Struggle), to oppose any negotiated settlement with the Dutch, which Sjahrir favoured. When Sjahrir resigned in February 1946, Tan Malaka was asked to form a Cabinet. The members of the coalition failed to reach accord, however, and Sjahrir was recalled. Tan Malaka then either attempted a coup or was caught up in the plans of others and was arrested on July 6, 1946, and held for two years without trial. On his release he supported a new political party, the Partai Murba (Proletarian Party). At that time the Dutch and Indonesians were at war for control of the country, Sukarno and Mohammad Hatta were prisoners of the Dutch, and much of the Communist leadership had been killed. In December 1948 Tan Malaka made a bid for control of the Indonesian revolution. From the city of Kediri, Java, which remained in Indonesian hands, Tan Malaka proclaimed himself head of Indonesia. When the Dutch attacked Kediri, he escaped but within a few months was captured and executed by supporters of Sukarno.

Tan Malaka wrote several political works; the best known is the autobiographical Dari Pendjara ke Pendjara (“From Prison to Prison”). He was a powerful, moving force in the creation of Indonesia but, after 1966 and the massacre of Communists, his name went into eclipse.